Field of the Invention
Embodiments of the present invention relate to a liquid crystal display device and an electronic pen system using the same.
Discussion of Related Art
Electronic pen systems are pens of a new concept that combines analog and digital, are just like a normal pen writing a character on a piece of paper, and written content is stored in a memory included in the pen, and the written content is sent back in the form of an image file to a computer to manage the transmitted content. Although the document written by the normal pen is scanned by a scanner (electronic color disassembler) to be stored in the form of an image file, the document written by the electronic pen system does not require the scanning process, and there is an advantage of being easily manageable through a separate program. Initially developed electronic pen systems should be connected to a computer. That is, in order to use the electronic pen systems, the computer always had to be turned on and there was the inconvenience of always having to be used near the computer. Also, when the content is stored in the computer, resolution of the image file is low, and it is difficult to exactly understand the content.
Currently, high performance electronic pens, which are capable of transforming written content into digital data, whenever connected to a computer, by storing the written content in a memory included in the electronic pens, are released. Furthermore, since a liquid crystal display is included in the electronic pen system itself, a product which can be directly written on the screen to check the content, and a digital pen, which can wirelessly transfer data without connection with a cable, have been developed, and a touch screen type which can detect position information of the electronic pen on the display or a technology having a detection sensor outside thereof to detect a movement path of the electronic pen, and/or the like is utilized.
In the touch screen type, or the technology using the outside detection sensor, as a size of the display is increased, a cost of the display is increased, and power consumption is greatly increased, and an accuracy of sensing the moving path of the electronic pen is decreased. Thus, a technology which minutely forms an information pattern including position information of a surface on a surface of the display to a degree beyond a determination by the human eye, and detects the information pattern using the electronic pen having the optical sensor to determine the position on the display is commercially available.
In the technology of detecting the information pattern using the above-mentioned electronic pen, in order to detect the information pattern by the electronic pen, the information pattern is formed to be optically distinguishable from a material layer on which the information pattern is formed. That is, an infrared light source is reflected from the display or a paper to be distinguishable from the information pattern, but the infrared light may not be reflected from some display devices. In this case, the information pattern is not distinguishable from the display device, and thus, the electronic pen recognizes an incorrect information pattern, and the movement path of the electronic pen is distorted.